1. Field of the Invention
The present invention relates to an undershoot/overshoot protecting circuit, in particular, to an undershoot/overshoot a protecting circuit for removing a noise of a waveform inputting circuit.
2. Description of the Related Art
Generally, crosstalk takes place due to stray coupling of adjacent signals. The crosstalk results in noise of a waveform. The amount of noise varies depending on the level of the waveform and the amount of overshoot or undershoot. Thus, to suppress noise caused by crosstalk, overshoot and/or undershoot should be prevented.
In a waveform inputting circuit for use with an LSI (Large Scale Integrated circuit), to prevent overshoot and/or undershoot from taking place, a clamp diode has been used.
However, in the conventional circuit using such a clamp diode, the through rate of the input waveform cannot be adjusted. Thus, when a waveform with a sharp leading/trailing edge is input, crosstalk takes place between leads of the LSI.
As described in Japanese Patent Laid-open Publication No. Hei6-35582, ringing tends to take place in a high speed bus. So far, the drawback of the above related art has not been solved.